To study the effects of environmental Particulate Matter (PM)_2.5 on the transcriptional profiles of Sprague Dawley (SD) rats lung tissue, thus providing insights into the mechanisms through which PM_2.5 may exert on human beings. Environmental PM_2.5 was prepared with versatile aerosol concentration enrichment system. The healthy control rats and the chronic obstructive pulmonary disease (COPD) model rats were exposed to PM_2.5 and clean air, respectively. RNA-sequence technique was used for genetic changes analysis in lung tissue after exposure, and the data were analyzed with transcriptional profile and pathway analysis. The results showed that persistent exposure to PM_2.5 caused various transcriptional changes related to signal pathways mainly including reactive oxygen species (ROS), inflammation, cell proliferation and so on. Compared with the healthy rats, the COPD model rats showed significant changes on cell proliferation, inflammation, immune response and cell death. Furthermore, after exposure to PM_2.5, COPD rats showed more significant pathway changes in ROS, inflammation, immune response, cell proliferation and damage repair. Collectively, PM_2.5 exposure caused similar but more significant transcriptional changes in COPD rats than in health rats or cleanair raised COPD rats, suggesting that human with COPD is more sensitive to PM_2.5 and more severe impairments might be induced after exposure. Humans whom are suffering COPD needs more protection from PM_2.5 to avoid lung injury.